Circuit breaker support structure



Nov. 28, 1961 H. FORWALD 3,011,097

CIRCUIT BREAKER SUPPORT STRUCTURE Filed June 2. 1959 Fig.

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INVENTOR. U f/aakon Fbrwa/d BY {Era/Q28 United States Patent 3,011,097 r CIRCUIT BREAKER SUPPORT STRUCTURE Haakon Forwald, Ludvika, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a Swedish corporation I Filed June 2, 1959, Ser. No. 817,632 Claims priority, application Sweden June 4, 1958 1 Claim. (Cl. 317-f-99) lator is electrically coordinated with a single pole of the I circuit breaker which is mounted on separate standoff insulators. In other more complicated relay systems, it is necessary to use two current transformers per pole where the transformers are connected on either side of the pole.

It is, thereby, known to arrange the current transformers inside the end standoff insulators of an interrupter pole. In this case, however, the height of the interrupter is increased by a distance equal to the length of the outwardly extendingterminal bushing of an interrupter unit when each of said standoff insulators carries two series connected interrupter units, each of said units consisting of a metal container enclosing a breaking gap one contact of which is carried by said terminal bushing inserted in one wall of the container and the other contact of which is electrically connected to the metal container.

The present invention now concerns a support structure for a high voltage circuit breaker including a plurality of standoff insulators. Said standoff insulators carry circuit interrupter units at an upper portion thereof, said circuit interrupter units being electrically connected in series and each comprising a metal container enclosing a breaking gap, one contact of which is electrically connected to said metal container. The standoff insulators lie in substantially the same plane and are aligned in a row. At each end of said row a bushing insulator for a current transformer is arranged to carry each one interrupter unit. Each current transformer comprises a high voltage winding, one terminal of which is electrically connected to the metal container of the interrupter unit carried by said current transformer.

By arranging the current transformers in this way the length of the circuitbreaker is somewhat increased, which, however, partly because of lack of space and partly for constructional reasons, must be decidedly pretors.

Accordingly, a primary object of this invention is to reduce the overall expense and space required of a high voltage circuit breaker and associated bushing insulator for a current transformer.

A further object of this invention is to utilize the bushing insulator of a current transformer as the standoff insulator for the interrupter chamber of a high voltage circuit breaker.

These and other objects of this invention will become apparent from the following description when taken in conjunction with the drawings, in which:

Referring now to the figures,

- ferred to an increase in height of all the standoff insula- 3,01 1,097 Patented Nov. 28, 1961 FIGURE 1 shows a side view of one pole of a high voltage air blast circuit breaker having a plurality of breaking contacts connected in series where the current transformer bushing insulator is additionally used for mounting one interrupter chamber of the breaker.

FIGURE 2 shows a top view of the system of FIG- URE 1. r

FIGURE 3 shows a circuit diagram of the system of FIGURE 1.

FIGURE 4 shows a previously known way to arrange the current transformers.

Referring now to FIGURE 1, the circuit interrupter system is carried by a compressed air chamber which has pillar insulators or standoff insulators 11,12, 13 and 14 directly fastenedthereto. through 14 carry interrupting chambers at their upper ends whereby standoff insulator 11 carries chamber 15; standoff insulator 12 carries chambers 16 and 17 (FIG- URE 2); standoff insulator 13' carries interrupting chambers 18 and 19; and standoff insulator '14 carries interrupting chamber 20.

Each of interrupting chambers 15*through 20 are of any desired type such as described in applicants copending application Serial No. 817,645 filed June 2, 1959, entitled Latch-Open Mechanism for Air Blast Circuit Breaker and assigned to the assignee of the present invention, which has become abandoned.

Forv purposes of the present invention, the internal construction of interrupters 15 through 20 is schematically shown in FIGURE 1 for interrupter 15. Thus, an operating mechanism 21 for interrupter '15 extends into an air-tight housing 22. The operating mechanism 21 operates to move a movable contact 23 into and out of bushing 25 is then connected in series with terminal bushing 26 associated with interrupter chamber 16 and this sequence is continued so that the contacts associated with interrupters 15 through 20 are all connected in series. The chamber 22 is normally under high pressure which is applied to chamber 22 through any convenient conduit means which is connected to the main air chamber 10 in the manner shown in the above noted copending application Serial No. 817,645. Accordingly, when the contacts of the various circuit interrupters open, an air blast will be brought into play upon the are created between the contacts to extinguish the are.

In the past, standoff insulators 11, 12, 13 and 14 would be of the normal type and at least one additional standoff insulator unassociated with the circuit interrupter chambers would be provided for supporting a current transformer which controls the operating mechanisms of the interrupters such as operating mechanism 21.

In accordance with the present invention, the end in sulators 11 and 14 are bushing insulators for the current transformers and additionally operate to carry the end interrupter units 15 and 20 as illustrated in FIGURE 2.

Note that while insulators 11 and 14 are bushing insulators for the current transformers, in accordance with the present invention, they are adapted additionally to carry the end interrupting chambers by the cross bar construction best seen in FIGURE 2 as cross bars 27 and 28 connected to the top of the insulators 11 and 14. In a similar manner, the normal standoff insulators 12 and 13 are provided with cross bars 29 and 30 which support interrupting chambers 16 to 17 and 18 to 19 respectively.

A circuit diagram of the resulting structure is shown in FIGURE 3 where the main circuit extends from for minal 34 of the current transformer through the primary winding 33 to terminal 35 and thereafter through the six schematically illustrated interrupters 15 through 20 and then to the second current transformer 39 carried by Standoff insulators 11 3 standoff insulator 14 to a second terminal of the circuit 40.

It will be noted that the only increase in length of the circuit intermpters of FIGURE 1 or 2, because of the use of the current transformer standoff insulators as supports for the circuit interrupters, is in the dimension a which is the length of chamber 15. This increase, in length, however, is of a substantially minor nature when compared to the great savings in cost and space by eliminating a separate transformer bushing insulator.

A previously known way to arrange the current transformers is shown in FIGURE 4 in which components similar to those of FIGURES 1 and 2 carry similar identifying numerals. Thus, FIGURE 4 difiers from FIGURES 1 and 2 in having interrupting chambers 15 through 20 symmetrically disposed on three standofi insulators 11, 12 and 14 with the standoff insulator -13 of the FIGURE 1 being eliminated. When each of the insulators 11, 12 and 14 of FIGURE 4 carries two interrupter chambers, the current transformers are mounted below insulator portions 4 1 and 42 so that the height of the interrupter is increased by a distance 12 which is the length of the extending terminal bushing of interrupter chamber 16. It is to be noted that not only the height of the breaker is increased but also that the electrical connection between the breaker and the transformer is more complicated.

What is claimed is:

A high voltage circuit breaker including a plurality of standoff insulators, first circuit interrupter units one carried at an upper portion of each insulator, said first circuit interrupter units'being electrically connected in series and each comprising a metal container enclosing a breaking gap one contact of which is electrically connected to said metal container, said plurality of standoff insulators lying in substantially the same plane and being aligned in a row, bushing insulators one at each end of said row, a current transformer insulator carried by each bushing, second interrupter units one carried by each current transformer connected in series with said first circuit interrupterunits and each including a metal container, each said current transformer comprising a winding one terminal of which is electrically connected to the metal container of the second interrupter unit carried by said current transformer.

References Cited in the fileof this patent UNITED STATES PATENTS 2,080,226 Paxton .1. May 11, 1937 2,238,636 Flurscheim Apr. 15, 1941 2,752,448 MacNeill June 26, 1956 

